1. Technical Field
The present invention relates to an image reading device and a method for reading an image.
2. Related Art
An image reading device such as a scanner has an image sensor, and provides the image sensor with a shift pulse so as to read an image line by line, e.g., as disclosed in JP-A-5-268476.
Then, the image read by the image sensor is transferred to an A/D converter line by line, and is converted into digital data.
Incidentally, it is known that an image transferred from an image sensor to an A/D converter is mixed with noise while being transferred, and the noise that the image being transferred is mixed with has periodic intensity in some cases.
In that case, positions of intensive and weak noise (peak and bottom positions of the noise) periodically overlaid on the respective lines are lined up in a vertical direction (sub-scanning direction) of a consequently produced image, resulting in an image in which the noise draws viewers' attention.